Objectives: The mechanism of the prenyltransferase reaction will be studied utilizing a number of fluro and sulfur analogues of the three substrates. 2. The enzymology of the prenyltransferase activities responsible for the synthesis of dolichols and CoQ side chain will be pursued. Studies to determine the regulation of carbon flow through the various prenyl transferase reactions will be initiated. 3. Purification of pig-liver squalene synthetase, which has been obtained in soluble form, will be attempted.